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Discussion Starter · #1 ·
1.8T AEB, manual

changing my oil and found this plug leading to a sensor unplugged. Is this supposed to be plugged in somewhere? I have no CEL's and I haven't even looked at this area in about 6 months. this sensor is found just above the oil filter location on 1.8T.

The pic below is looking down on the top corner of the engine block (intake manifold side). the bright white thing in the bottom left corner of the pic is the intake manifold. I'm wondering that small black plug leading to the white bell-shaped sensor in the middle of the pic. Many thanks in advance! :thumbup:



hmm.. can't get the pic to show up in here. Here's the link:
http://ca.pg.photos.yahoo.com/ph/moochayo/detail?.dir=c520&.dnm=8c21scd.jpg
 

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Discussion Starter · #5 ·
ok, front O2 sensor. that's what my hunch was. But where does it plug into? It's a small 2-wire plug.
 

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I'm pretty sure that's the front O2 sensor.
Umm how did you come up with that:hmmm:

It appears to be the oil pressure sensor, as you can see the oil filter right below it.

There should be a clip that goes in to the wireharness on the fire wall that it plugs in to. Suprised you dont have a low/no oil pressure light.
 

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Discussion Starter · #7 ·
OK, maybe I'm blind, or the receptor is really hidden, but I cannot find an empty receptor anywhere that this plugs into.

I looked on the firewall, and all the electrical plugs are connected.

the plug is a single line with two pins (approx 1 cm wide). The line is black-shrink-wrapped and it looks like that sensor joins into it, or something like that.

Could this be a diagnostic plug?
 

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Nope, its the oil pressure sensor, I will take a pic of the receptacale if you want, I have to move it when I installed my oil pressure service.
 

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Discussion Starter · #9 ·
Nope, its the oil pressure sensor, I will take a pic of the receptacale if you want, I have to move it when I installed my oil pressure service.
Wow... That would be really helpful! Thanks!
 

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If this was the front O2 sensor that was unplugged, the car would be throwing a MIL, as that is about the most important sensor to the proper operation of the engine.

SirWired
 

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yeah, looks like the oil pressure sensor. but if you connect it, then you should get the "low oil pressure" warning light, unless someone bypassed it...
 

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Discussion Starter · #13 ·
yeah, looks like the oil pressure sensor. but if you connect it, then you should get the "low oil pressure" warning light, unless someone bypassed it...
So it's supposed to be plugged in then, I assume?
I've owned the car for 7 years and never had a problem with oil pressure... well, never had an indication of oil pressure problem. I'm not sure where it would have been bypassed since I have been doing maintenance for hte past few years.

Shouldn't there be a CEL if the sensor is not plugged in? Can I check it with VAG? which block?

thx for all the help!
 

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I just looked at the same harness and 1 wire (white) runs to the oil pressure switch, the other one is hanging loose with a black terminal housing.

I looked it up in ETOS and it says the loose wire should run to a oil temperature gauge sender, but there isn't any. Apparently VW uses a common engine wire harness, some engines have a oil temp sender and some don't which is why it's not connected in that case.
 

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So it's supposed to be plugged in then, I assume?
I've owned the car for 7 years and never had a problem with oil pressure... well, never had an indication of oil pressure problem. I'm not sure where it would have been bypassed since I have been doing maintenance for hte past few years.

Shouldn't there be a CEL if the sensor is not plugged in? Can I check it with VAG? which block?

thx for all the help!
no CEL, just the warning light.
 

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I just looked at the same harness and 1 wire (white) runs to the oil pressure switch, the other one is hanging loose with a black terminal housing.

I looked it up in ETOS and it says the loose wire should run to a oil temperature gauge sender, but there isn't any. Apparently VW uses a common engine wire harness, some engines have a oil temp sender and some don't which is why it's not connected in that case.
if that's the case, then simply trace the wire back to the connector, unplug it, and start up the engine. if the warning light comes on, then your sensor is functional.
 

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^ correct.

I thought the OP was asking about the wire/connector hanging loose. According to his picture the oil pressure sensor is correctly connected (1 wire).

The oil pressure sensor is a 1-wire sensor, as well as the oil temp sensor. Some engines do have a temp sensor and some don't. If the engine doesn't have a oil temp sensor 1 wire/connector will hang loose.
 

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Discussion Starter · #18 ·
^ correct.

I thought the OP was asking about the wire/connector hanging loose. According to his picture the oil pressure sensor is correctly connected (1 wire).

The oil pressure sensor is a 1-wire sensor, as well as the oil temp sensor. Some engines do have a temp sensor and some don't. If the engine doesn't have a oil temp sensor 1 wire/connector will hang loose.
Ok, that explains it. This means that the plug is not necessary to be plugged in for safe operation then right?

And if I understand you correctly... If I wanted to get a oil temp gauge, it's simply a matter of hooking into this disconnected connector right? ACtually, NVM... I just reread your post. A oil temp sensor would connect to that loose connector, not just the gauge.
 

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Ok, that explains it. This means that the plug is not necessary to be plugged in for safe operation then right?

And if I understand you correctly... If I wanted to get a oil temp gauge, it's simply a matter of hooking into this disconnected connector right? ACtually, NVM... I just reread your post. A oil temp sensor would connect to that loose connector, not just the gauge.
Yes, some engines codes (other than ours) have a oil temp sensor besides the oil pressure switch. VW installed an engine wire harness with the oil temp sensor wire on it no matter what. That's why its hanging loose on our engines. #17 is the wire to the oil temp sensor (if present) #26 is the bell-shaped wire/grommet to the oil pressure switch.

 
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